During the second and third trimesters of pregnancy, some safe and effective alternatives to abdominal crunches include the following exercises:

1. Start in a quadruped position (forearms and knees), exhale as you tighten your abs, pulling your belly button in toward your backbone. Inhale as you release the abdominal muscles. Be aware of keeping your back flat and using the abdominal muscles; this exercise is different than a pelvic rock. Do 15–25 repetitions.

2. You can work your obliques (the muscles that run diagonally around your torso) by starting in a side-lying position with knees bent at a 45-degree angle. Exhale as you lift your rib cage toward your top hipbone, squeezing in the waistline. Inhale as you lower. Do 10–20 repetitions, then repeat on your other side.

These exercises should be combined with pelvic floor or Kegel exercises for maximum benefit.